How to Check a Wheel Hub Bearing Assembly
It can be a challenging task to properly diagnose a damaged hub bearing assembly. This video will help you to recognize common causes of noise generation and know how to examine a hub bearing assembly.
This video is not intended to substitute for the specific recommendations of your vehicle manufacturer. Depending on the application, type of hub bearing assembly and location, processes may vary. Please review the vehicle manufacturer’s recommendations before removing or installing components. Proper maintenance and handling practices are critical. Failure to follow all installation instructions can result in equipment failure, creating a risk of serious bodily harm.
The first step is to verify the source of any unfamiliar noise. Often, this can be attributed to road surface conditions such as newly paved roads or roads with uneven surface characteristics, which can cause unusual and intensified noises. For example, a recently paved surface may have a series of small recesses that cause a continuous dull humming sound. The tread design, composition, and wear patterns of vehicle tires can be another source of unfamiliar noise. Unusual wear patterns are generally caused by lack of tire rotation, poor alignment, improper pressure, or worn suspension parts.
After eliminating noise generation caused by road surface conditions, tire design, and wear patterns, it’s time to make a more detailed examination of the wheel assemblies as well as the hub bearing assemblies. Prior to checking a hub bearing assembly, make sure you have the proper tools. Perform a hand rotation check on the wheel. Next, grasp the wheel at the nine and three o’clock positions. Push while oscillating and also pull while oscillating the wheel. Perform a second check following this same procedure, grasping the wheel at the twelve and six o’clock positions. In addition, listen and feel for roughness. After making all preliminary inspections, check the hub bearing assembly more precisely.
If applicable, remove the wheel cover to access the lug nuts. Remove the lug nuts and the wheel and tire assembly. Next, remove the caliper from the caliper mounting bracket. To prevent damage to the brake line due to the weight of the caliper, make sure the caliper is properly supported with either an s-hook or a piece of wire. Remove the caliper mounting bracket and then remove the brake rotor. Rotate the hub bearing assembly by hand. Bearings normally do not loosen up under typical use. If the hub bearing assembly appears to be loose, the bearing may be damaged. The axle hut may have backed off or the axle nut may not have been properly clamped. Any roughness, looseness, or noise from the bearing is an indication that the bearing is damaged and needs to be replaced.
To check a hub bearing assembly’s internal clearance, a dial indicator with a magnetic base is required. To obtain accurate readings from the dial indicator, it is important to thoroughly clean and smooth the surfaces where the dial indicator base and tip will be placed. Carefully use a fine file, wire brush, emery cloth, or honing stone as appropriate to remove any debris, nicks, or burrs. The dial indicator base should be placed rigidly on the knuckle or a secure portion of the suspension. When setting the dial indicator tip, the indicator itself should have ample travel for the variation around the face.
Position the indicator tip perpendicular on the wheel pilot, as close to the center of the hub bearing assembly as possible. This will provide the most accurate results. Grasp the wheel flange at the three o’clock and nine o’clock positions and push while oscillating the hub bearing assembly approximately 90 degrees side to side at least five times. Set the dial indicator to zero. Next, pull while oscillating the hub bearing assembly approximately 90 degrees side to side at least five times. Proper loading and oscillation is necessary in order to fully seat the bearings. Observe the total indicator movement. If it exceeds 0.004 inches, replace the hub bearing assembly.
When any symptoms or visual signs of premature wear are experienced, immediate action is required. The hub bearing must be replaced. Failure to replace the hub bearing may result in severe damage, which could include loss of steering control or a wheel separation, creating a risk of serious bodily injury.